Valve-motion for steam-engines



(No Mode1 W.` G CEAPIN. VALVE MOEIONEOE STEAM ENGINES.'

Patented Juliy 14","1885;

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d INTOR f A W'TNESSES; l

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UNITED STATES PATENT OFFICE.-

WILLIAM G. cI-IAPIN, OE BROOKLYN, NEwT YORK, ASSIGNOR, RY DIRECT AND MESNE ASSIGNMENTS, To JAMES T. IIALSEY, OE RIOIIMOND, VIRGINIA.

VALVE-MOTION FOR STEAM-ENGINES.

SPEAIIEVICATION forming part of Letters Patent No. 322,348, dated July 14, 1885.

Application led April 16,1833. (No model.)

To all Vwhom it may concern,.-

Be it known that I, WILLIAM G. CHAPIN, of the city of Brooklyn, county of Kings, and State of New York, have invented a new and useful Valve-Motion for Steam-Engines, of

which the following is a speciiication.

My invention relates to that class of steamengines in which steam is alternately admitted to opposite ends of the steam-cylinder I0 through suitable ports by means of a main valve adapted to slide over these ports, and to that class of valves -in which the supply of steam is admitted through suitable openings or passages in the main valve and cut off by means of a secondary or cut-oft" valve sliding upon the main valve and over the openings in it. i

rlhe objectof my invention iS to provide a simple and effective means for giving a proper motion to the secondary or cut-oft` valve.

A preferred form of a convenient embodiment of my invention is hereinafter described and claimed.

In the accompanying drawings, Figure l is a view in Side elevation of. the steam-chest, main valve, cut-off valve, and my apparatus for giving motion to said cut-off valve. Fig. 2 is a partial detailed view in side elevation of a modied form of my apparatus, as hereinafter set forth; Fig. 3, an end elevational View of the modified apparatus represented in Fig. 2, and Fig. 4 a top plan detail of the same. Figs. 5, 6, 7, 8, 9, and are respectively central sectional elevational details through the main valve and the cutoff valve,`represent ing their positions with respect the one to the other during a half-revolution of the eccentric, and also representing the respective positions of said valves with regard to the ports in the steam-chest and the respective positions of the centers of the eccentric, the shaft, and of the pins or points of attachment of the two valve-stems to the eccentric-strap, as hereinafter more fully explained.

In the drawings, A is the eccentric, and B the .eCcentricSha-ft, to which the eccentric is rigidly connected inI the usual manner.

C is the eccentric-strap, which is applied to the eccentric so as to be actuated thereby, and

valve-stems and valves.

is designed, in connection therewith, to afford a means of connection and actuation for the D is the main valve, and E the cut-off valve.

, F Ais "the steam-chest.

G is the valve-Stem4 which operates the main valve, and H the valve-stem which op? crates the cut-off valve. These stems are connected on the one hand in the usual manner with the valves, and on Athe other hand are connected with the eccentric-strap by means of the pins I and J, I connecting the valvestem G of the main valve, and J stem H ofthe cut-oft' valve.

the valve-` K is an arm pivoted to the eccentric-strap,

and also to the bed ofthe engine or other fixed support exterior to the strap, by means of the pivot L. In the construction repref sented in Fig. 1thiS arm is pivoted to theV strap by means of the pivot Lwhich connects thevalve-stem G of the main valve to saidi` strap.

M M are ports in the steam-chest F.

O OX are steam passages or openings in the main valve.

Such being a description of a convenient embodiment of my invention, its operation -I will be readily understood. The movement of the eccentric upon its shaft actuates the eccentric-strap, which in turn, subject to the control of the arm, actuates the valve-stems,

which in turn operate the valves in the usual manner.

The object of the arm is simply to guide the motion ofthe pin I in the direction of the motion of the valve.

The main valve herein mentioned is the wellknown plain slide-valve for admitting steam into the ports M M through the passages A O OX. The setting 'and the motion of this valve are not dierent from those adopted for the operation of plain slide valves of this character generally.

The cut-off or secondary valve, which slides upon the main valve, is connected by means ofthe valve-stem H and the pinJ with the eccentric-strap C.I f Y The position' of the pin J with respect to the pin I is such that a line through the center of the two would be perpendicular to a line through the pin I and the center S of the eccentric.

R represents the center of the shaft, and the arrow V the position of the crank-pin relatively to the position of the eccentric.

lThe length of the cut-off valve with respect to the distance between the outer edge of the passage O and that of the passage OX, may be varied at will, so as to effect an earlier or later closure of the cut-off valve.

In the detailed views, respectively numbered Figs. 5 to 10, I have represented the various positions of the two valves with respect to each other, to the ports in the steam-chest, and to the various positions of the pins I and J and the centers of the eccentric and of its shaft. The lettering` in these figures corresponds to the lettering in Fig. 1, and while I vhave illustrated in full drawings the positions of the valves, I have simply indicated by diagraphic lines and the letters by which I have denominated them-the pins and the centers referred to.

"In Fig. 5 the piston is at one end of its stroke, the main valve is about to open, and the cut-off Valve is wide open. In Fig. 6 the crank is supposed to have turned one-twelfth of a revolution, the main valve is nearly open, and the cut-oft` also is nearly open. In Fig. 7, at one-sixth of a revolution the main valve is wide open and the cut-off valve has just closed. In Fig. 8, at one-quarter of a revolution or one-half stroke, the cut-off remains nearly at rest on the main valve. In Fig. 9, at three-quarters stroke, the main valve closes and the cut-off is beginning to move more rapidly upon it, and in Fig. l0 the cut-off valve has reached the full limit of its travel upon the main valve.

In all of the above gures the left-hand eX- tremities of the valves are those considered.

These diagrams taken together are illustrative of the respective positions of the several members and parts at various stages of one half oi' a revolution ofthe eccentric. The positions during the remaining half of the revolution are correspondingly opposite, and may be considered as represented by the positions of the corresponding parts considered upon the opposite (right hand) ends of the valves from those considered in the description ofthe iigures referred to.

By the above arrangement I am enabled to make the motion of the cutoff valve most rapid when the main valve is at the end of its travel, so that I am enabled also to open the valves wide enough to give the steam a ready entrance, and then to close them with a quick motion as early or as late in the stroke as I desire, and accomplish the same by means so simple and positive in its action as to insure entire reliability.

I have represented in Figs. 2, 3, and 4 the arm K, connected to the eccentric-strap at a point, Z, intermediate between the pinsI and J. This construction effectuates the same result as the construction first described, and, so far as said result goes, it would be practically the same, whether the connection is made above or below the pivot I, provided it be on a line through the pivots I and J.

In practice the construction represented in Figs. 2, 3, and 4 is, perhaps, the most available.

I have shown a `dat sliding valve; but my invention is equally applicable to a round piston-valve.

While said invention as herein described is applied to a steam-engine, it is, of course, equally applicable to an air-engine employing a kindred construction of valves.

I do not claim as novel with me the use of a main valve provided with a cut-off valve sliding upon it; nor yet of an eccentric,strap to which two valve-stems are attached; but

What I do claim, and desire to secure by Letters Patent, is-

1. The combination, in an air or steam engine, of a steam-chest, a main valve operating in connection therewith, a cut-off valve sliding upon said main valve, a valve-operating eccentric, an eccentric-strap surrounding and actuated by said eccentric, a valve rod or stem piloted to said eccentric-strap""ahiconnected direct with the main valve, and a valve rod or stem likewise pivoted to said eccentric-strap and connected direct with the cutoff valve, the arrangement and operation being substantially such as are hereinbefore set forth.

2. 'Ihe combination, in an air or steam engine, of a steam-chest, a main valve operating in connection therewith, a cut-off valve sliding upon said main valve, a valve-operating eccentric, an eccentric-strap surrounding and actuated by said eccentric, a valve rod or stem pivoted to'said eccentric-strap and connected direct with the main valve, a valve rod or stem likewise pivoted to said eccentric-strap and connected direct with the cut-off valve, and a rocking arm pivoted to a iixed point exterior to the eccentric-strap and also pivoted to said eccentric-strap, substantially as and for the purposes specified.

3. The combination, in an air or steam engine, of a steam-chest, a main valve operating in connection therewith, a cut-oft` Valve sliding upon said main valve, a valve-operating eccentric, an eccentric-strap surrounding and actuated by said eccentric, a valve rod or stem pivoted to said eccentric-strap and connected direct with the main valve, a valve rod or stem likewise pivoted to said eccentricstrap and connected direct with the cut-off valve, and a rocking arm pivoted to a fixed point exterior to the eccentric-strap and also pivoted to said eccentric-strap at a point coincident with the pivot of the main valvestem, substantially as and for the purposes specied.

4. The combinatiomto form avalve-gearing IOO IIO

for an air or steam engine, of a. steam-chest, strap-controlling arm pivoted toa fixed point a main valve operating in connection thereexterior to said arm and alsopivoted to said with, a cut-oft' valve sliding upon the main strap at a pointvon a line joining the pivots` valve7 a valve-operating eccentric, an eccenof the4 valve-stems, substantiallyas set forth.`

5 tric-strap connected With and actuated by said In testimony whereof Ihave hereunto signed 15 eccentric, a. valve-rod pivoted to the eccentric my naine this 3d day of February, A. D. 1883.

and connected direct with the main valve, a W; G. CHAPIN. second valve-:rod `pivoted to the eccentric in In presence o'-` t line above the valve-rod last mentioned and CHARLES P. FLANIGAN,

1o connected direct with the cut-ofvvalve, anda J oHNfMcKIcoL. 

